Internal-combustion engine



Aug, 26 1924;; mwaa H. WIEDERKEHR INTERNAL COMBUSTION ENGINE Filed Oct 2, 1922 Patented Aug. 26, 1924.

UNITED STATES PATENT OFFIICIE.

HANS WIEDERKEHR, OF ZURICH, SWITZERLAND, ASSIGNOR T FIRM SCHWEI- ZERISCHE LOKOMOT'IV- & MASCHINENFABRIK Q1? WINTERTHUIR, SWITZER- LAND,

INTERNAL-COMBUSTION ENGINE.

. Application filed October 2, 1922. Serial No. 591,953.

T 0 all whom it may corncem: 7

Be it known that l, HANS WIEDERKEHR, a citizen of the Republic of Switzerland, residing at Zurich, Switzerland, have invented certain new and useful Improvements I in Internal-Combustion Engines, of which the following is a specification, reference bein had therein to the accompanying drawing. The invention relates to improvements in 10 internal combustion engines and particularly to a fuel pump for such engines working with direct injection of the fuel. In contradistinction to Diesel-en ines with engines of the above type the fue is'not injected into the cylinder by means of compressed air,

but by means of a fuel pump and a nozzle.

A complete atomizing of the fuel is very essentialfor attaining a good combustion,-

the complete atomizing requires a fuel jet of uniform strength during the whole period of injection and the start and the termination of the injection should'take place almost instantaneously in order .to prevent the formationof drops at the opening of the nozzle. These requirements can be attained for instance by the provision of a mechanically operated valve inserted in the fuel conduit in front of the nozzle, the fuel being then always under pressure in front of the valve.

According to the resent invention the same end is obtains by a fuel pump by means of which the fuel is directly injected into the combustion space through the open nozzle andwhich pump is so designed that the compression period is limited to the period in which the pump piston has its greatest speed. This is attained by determining the beginning and the termination of the compression period at the closing andthe opening the suction valve in suitable moments; the control of the suction valve being derived from the movement of the pump piston.

it is known with Diesel-engines to regulate the quantity delivered" by the fuelpump by controlling thesuction valve, but the termination of the discharge is effected when the pump piston is in one of its dead gradually the manner in which the fuel is supplied being of no importance with Diesel engines.

A constructional example of the subject matter of the invention is shown on the accentre positions, so that the discharge ceases" companying drawing, showing a vertical section through the fuel pump. The extreme positions of the various levers being diagrammatically indicated by dotted lines.

The piston C of the pump is reciprocated by the eccentric E, the stroke of the piston is indicated b H. The fuel is supplied by the pipe Z; 5 denotes the controllably arranged suction valve having a portion extending in the downward direction, D is the automatic pressure valve and L denotes a pipe leading to the fuel nozzle. K and M are controlling levers operated by the piston C. The fulcrums X and Y of the levers K and M respectively are formed by the pins of small cranks; the axles of the cranks pass throu h the casing of the pump and carry outsi' e the casing the levers N and 0 respectively, which levers can be turned by the link R connected to the sleeve of a governor G.

In thelower dead center position of the piston C, at which point the compression stroke begins when theeccentric is rotated in the directionof the arrow P, the suction valve S rests on the one end of the upper lever K and in this position the valve body is lifted above its seat to a small extent so that fuel displaced by the piston C moving in the upward direction can escape through the open suction valve. Upon the further upward movement of the piston G the suction valve S is no longer supported by the lever K and is .pressed down on its seat by the action of the spring T, and fuel is now forced through the pressure valve into the nozzle. The compression period starts when the pump piston moves at its greatest speed and lasts during the angular turn. of the eccentric indicated by the angle W. 'When the eccentric has been turned through said angle and when it isin the position F the compression period is interrupted as the lower leverM abuts against the extension S of the suction valve Sand lifts the latter. The fuel which is further displaced by the piston C escapes through the open suction valve.

By means of an adjustment of the lever N the fulcrum of the upper lever K is raised or' lowered and thereby the suction valve will sooner or later be pressed on its seat, i. e., the beginning of the compression period will occur sooner or later. When the level 0 is adjusted by a turning movement in the clockwise direction, the fulcrum Y of the lower lever M is raised, the suction valve Will be lifted off its seat earlier Whereby the termination of thenompressiOn period is caused, the angle W during Which the compression period-takes place is thereby decreased. The adjustment of the levers N and 0 may be carried out simultaneously or the levers may be singly adjusted either by hand or by a governor.

I claim: 1. In a fuel pump for internal combustion engines, the combination of a cylinder, its plunger, a fuel supply a valve controlling the connect'ion 'between said'fuel supply and said cylinder, a lever operating in unison With'said plunger and controlling said valve to determine the beginning of the pressure stroke, a second lever operating in unison With said lunger and controlling said valve to determine the end of the pres-' sure stroke and means adapted to alter the stroke of said levers so that the beginning as Well as the end of the pressure stroke is altered. v

In a fuel pump for internal combustion engines, the combination pf a cylinder, its plunger, a fuel supply, a valve controlling the connection between said fuel sup-- ply and said cylinder, a lever pivoted on an eccentric fulcrum and operating in unison said plunger and controlling said valve todetermine the end of the pressure stroke,

and means to alter the eccentricities of said fulcrums so that the beginning as well as i the end of the pressure stroke is altered.

3. In a fuel pump for internal combus tion engines, the combination of a cylinder, its plunger, a fuel supply, a valve controlling the connection between said fuel supply and said cylinder, a leverpivoted on an eccentric fulcrum and operating in unison with said plunger and controlling said valve to determine the beginning of the pressurestroke, a second lever pivoted on an eccentric fulcrum and operating in unison with said plunger and controlling said valve to determine'the end of the pressure stroke, and means operatively connected to a governor to alter the eccentricities of the fulcrums' so that the beginning as Well as the end of the pressure stroke is altered.

In testimony whereof Ialfix my signature.

HANS WI'EDERKEHR. 

